1
|
Miettinen PJ, Ebner R, Lopez AR, Derynck R. TGF-beta induced transdifferentiation of mammary epithelial cells to mesenchymal cells: involvement of type I receptors. J Biophys Biochem Cytol 1994; 127:2021-36. [PMID: 7806579 PMCID: PMC2120317 DOI: 10.1083/jcb.127.6.2021] [Citation(s) in RCA: 746] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The secreted polypeptide transforming growth factor-beta (TGF-beta) exerts its multiple activities through type I and II cell surface receptors. In epithelial cells, activation of the TGF-beta signal transduction pathways leads to inhibition of cell proliferation and an increase in extracellular matrix production. TGF-beta is widely expressed during development and its biological activity has been implicated in epithelial-mesenchymal interactions, e.g., in branching morphogenesis of the lung, kidney, and mammary gland, and in inductive events between mammary epithelium and stroma. In the present study, we investigated the effects of TGF-beta on mouse mammary epithelial cells in vitro. TGF-beta reversibly induced an alteration in the differentiation of normal mammary epithelial NMuMG cells from epithelial to fibroblastic phenotype. The change in cell morphology correlated with (a) decreased expression of the epithelial markers E-cadherin, ZO-1, and desmoplakin I and II; (b) increased expression of mesenchymal markers, such as fibronectin; and (c) a fibroblast-like reorganization of actin fibers. This phenotypic differentiation displays the hallmarks of an epithelial to mesenchymal transdifferentiation event. Since NMuMG cells make high levels of the type I TGF-beta receptor Tsk7L, yet lack expression of the ALK-5/R4 type I receptor which has been reported to mediate TGF-beta responsiveness, we evaluated the role of the Tsk7L receptor in TGF-beta-mediated transdifferentiation. We generated NMuMG cells that stably overexpress a truncated Tsk7L type I receptor that lacks most of the cytoplasmic kinase domain, thus function as a dominant negative mutant. These transfected cells no longer underwent epithelial to mesenchymal morphological change upon exposure to TGF-beta, yet still displayed some TGF-beta-mediated responses. We conclude that TGF-beta has the ability to modulate E-cadherin expression and induce a reversible epithelial to mesenchymal transdifferentiation in epithelial cells. Unlike other transdifferentiating growth factors, such as bFGF and HGF, these changes are accompanied by growth inhibition. Our results also implicate the Tsk7L type I receptor as mediating the TGF-beta-induced epithelial to mesenchymal transition.
Collapse
|
research-article |
31 |
746 |
2
|
Ebner R, Chen RH, Shum L, Lawler S, Zioncheck TF, Lee A, Lopez AR, Derynck R. Cloning of a type I TGF-beta receptor and its effect on TGF-beta binding to the type II receptor. Science 1993; 260:1344-8. [PMID: 8388127 DOI: 10.1126/science.8388127] [Citation(s) in RCA: 313] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Transforming growth factor-beta (TGF-beta) affects cellular proliferation, differentiation, and interaction with the extracellular matrix primarily through interaction with the type I and type II TGF-beta receptors. The type II receptors for TGF-beta and activin contain putative serine-threonine kinase domains. A murine serine-threonine kinase receptor, Tsk 7L, was cloned that shared a conserved extracellular domain with the type II TGF-beta receptor. Overexpression of Tsk 7L alone did not increase cell surface binding of TGF-beta, but coexpression with the type II TGF-beta receptor caused TGF-beta to bind to Tsk 7L, which had the size of the type I TGF-beta receptor. Overexpression of Tsk 7L inhibited binding of TGF-beta to the type II receptor in a dominant negative fashion. Combinatorial interactions and stoichiometric ratios between the type I and II receptors may therefore determine the extent of TGF-beta binding and the resulting biological activities.
Collapse
|
|
32 |
313 |
3
|
Gitelman SE, Kobrin MS, Ye JQ, Lopez AR, Lee A, Derynck R. Recombinant Vgr-1/BMP-6-expressing tumors induce fibrosis and endochondral bone formation in vivo. J Biophys Biochem Cytol 1994; 126:1595-609. [PMID: 8089189 PMCID: PMC2290953 DOI: 10.1083/jcb.126.6.1595] [Citation(s) in RCA: 130] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Members of the TGF-beta superfamily appear to modulate mesenchymal differentiation, including the processes of cartilage and bone formation. Nothing is yet known about the function of the TGF-beta-related factor vgr-1, also called bone morphogenetic protein-6 (BMP-6), and only limited studies have been conducted on the most closely related factors BMP-5, osteogenic protein-1 (OP-1) or BMP-7, and OP-2. Because vgr-1 mRNA has been localized in hypertrophic cartilage, this factor may play a vital role in endochondral bone formation. We developed antibodies to vgr-1, and documented that vgr-1 protein was expressed in hypertrophic cartilage of mice. To further characterize the role of this protein in bone differentiation, we generated CHO cells that overexpressed recombinant murine vgr-1 protein. Western blot analysis documented that recombinant vgr-1 protein was secreted into the media and was proteolytically processed to yield the mature vgr-1 molecule. To assess the biological activity of recombinant vgr-1 in vivo, we introduced the vgr-1-expressing CHO cells directly into the subcutaneous tissue of athymic nude mice. CHO-vgr-1 cells produced localized tumors, and the continuous secretion of vgr-1 resulted in tumors with a strikingly different gross and histological appearance as compared to the parental CHO cells. The tumors of control CHO cells were hemorrhagic, necrotic, and friable, whereas the CHO-vgr-1 tumors were dense, firm, and fibrotic. In contrast with control CHO tumors, the nests of CHO-vgr-1 tumor cells were surrounded by extensive connective tissue, which contained large regions of cartilage and bone. Further analysis indicated that secretion of vgr-1 from the transfected CHO tumor cells induced the surrounding host mesenchymal cells to develop along the endochondral bone pathway. These findings suggest that endochondral bone formation.
Collapse
|
research-article |
31 |
130 |
4
|
Arrick BA, Lopez AR, Elfman F, Ebner R, Damsky CH, Derynck R. Altered metabolic and adhesive properties and increased tumorigenesis associated with increased expression of transforming growth factor beta 1. J Cell Biol 1992; 118:715-26. [PMID: 1639853 PMCID: PMC2289543 DOI: 10.1083/jcb.118.3.715] [Citation(s) in RCA: 127] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Transforming growth factor-beta (TGF-beta) is a potent mediator of cell proliferation and extracellular matrix formation, depending on the cell type and the physiological conditions. TGF-beta is usually secreted in a "latent" complex that needs activation before it can exert its effects. Several observations correlate increased expression of TGF-beta 1 with tumorigenesis. To evaluate the physiological relevance of increased TGF-beta 1 synthesis in tumor cells we established cell clones overexpressing TGF-beta 1 and observed the resulting physiological changes in TGF-beta overproducing cells in vitro and in vivo. As a model system we used the human E1A-transformed 293 tumor cells, which are insensitive to the direct growth modulatory effects of TGF-beta. The selection of this cell line allows an assessment of physiological alterations independent of TGF-beta induced proliferative changes. The use of two TGF-beta 1 expression vectors containing either the natural or a modified TGF-beta 1 precursor cDNA permitted the establishment of separate 293 cell lines overexpressing latent or active TGF-beta. Comparison of the resulting changes in glycolytic rate, adhesiveness and integrin and plasminogen activator expression established that, in vitro, both types of clones behaved similarly, indicating that expression of latent TGF-beta induces autocrine changes in the tumor cells and thus suggesting that some level of cell-associated activation occurs. TGF-beta overexpression resulted in an increased metabolic rate due to enhanced glycolysis, a property long associated with tumor cells. This increased glycolysis was not associated with altered proliferation. Cells overexpressing TGF-beta also displayed enhanced fibronectin mRNA and plasminogen activator synthesis and increased adhesiveness in vitro. They showed enhanced survival when plated sparsely on plastic in the absence of serum, and attached more readily to laminin. In addition, synthesis of several beta 1 integrins, in particular the alpha 1/beta 1, alpha 2/beta 1, and alpha 3/beta 1, all of which recognize laminin, were enhanced. Finally, cells overexpressing active TGF-beta, but not latent TGF-beta, also showed increased tumorigenicity in nude mice. Thus, an increase in endogenous TGF-beta synthesis confers several proliferation-independent phenotypic changes which may be of significance for the survival of the tumor cell inoculum or its subsequent growth, and for tumor formation and development. In the case of cells expressing active TGF-beta, the release of active TGF-beta into the vicinity of the tumor cells may also result in a more hospitable environment for tumor growth.
Collapse
|
research-article |
33 |
127 |
5
|
Pennington DW, Lopez AR, Thomas PS, Peck C, Gold WM. Dog mastocytoma cells produce transforming growth factor beta 1. J Clin Invest 1992; 90:35-41. [PMID: 1634619 PMCID: PMC443060 DOI: 10.1172/jci115853] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Transforming growth factor-beta (TGF beta) promotes deposition of extracellular matrix and is associated with fibrotic conditions both in experimental animals and in humans. Although a role for mast cells has been suspected in the pathogenesis of fibrosis, no potent mediator capable of stimulating fibroblast growth or extracellular matrix deposition has been identified in mast cell supernatants. We report here the constitutive production of TGF beta 1 by four dog mastocytoma cell lines. TGF beta 1 was identified by characteristic biologic activity, blockade of biologic effect by specific neutralizing antibody, and by recognition of a band with the appropriate migration by western blot. TGF beta 1 mRNA, but not TGF beta 2 or TGF beta 3 mRNA, was also produced constitutively by all four cell lines. Quantitation by bioassay revealed baseline TGF beta secretion of approximately 1 ng/10(6) cells over 48 h. Stimulation of mastocytoma cells with phorbol ester increased the rate of release of TGF beta 1, most markedly in the first 30 min after stimulation, without increasing TGF beta 1 mRNA. Dog mastocytoma cells produced TGF beta 1 primarily in a latent form, inactive until treated with acid. Both pure TGF beta 1 and TGF beta-containing mastocytoma cell-conditioned media inhibited mitogenesis and proliferation in dog mastocytoma cell lines, suggesting that mast cell tumor lines would not grow preferentially based on their ability to produce TGF beta. These studies may make possible further investigation of the mechanism by which mast cells contribute to the induction of fibrosis.
Collapse
|
research-article |
33 |
70 |
6
|
Lawler S, Candia AF, Ebner R, Shum L, Lopez AR, Moses HL, Wright CV, Derynck R. The murine type II TGF-beta receptor has a coincident embryonic expression and binding preference for TGF-beta 1. Development 1994; 120:165-75. [PMID: 8119124 DOI: 10.1242/dev.120.1.165] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have isolated cDNAs of the murine type II TGF-beta receptor and have found a conserved cytoplasmic domain, but a less extensive homology in the extracellular receptor domain between the human and murine homologues. In situ hybridization analysis of the mouse fetus during mid gestation localized the expression of this receptor to various developing tissues, primarily in the mesenchyme and epidermis. This expression pattern correlates well with the expression of TGF-beta in general and especially TGF-beta 1, suggesting that TGF-beta 1 exerts its developmental role through this receptor in an autocrine or paracrine fashion. Type II receptor expression was not detected in the central nervous system and developing cartilage. These tissues lack TGF-beta 1 expression but express TGF-beta 2 and/or TGF-beta 3, suggesting that they may exert their activities through separate receptor isoforms. In addition, the efficient binding of TGF-beta 1, but not TGF-beta 2, to the cloned type II receptor strengthens the likelihood that additional type II receptor isoforms exist which display preferential binding to TGF-beta 2 and have their own defined role in development.
Collapse
|
|
31 |
63 |
7
|
Arriola EL, Lopez AR, Chresta CM. Differential regulation of p21waf-1/cip-1 and Mdm2 by etoposide: etoposide inhibits the p53-Mdm2 autoregulatory feedback loop. Oncogene 1999; 18:1081-91. [PMID: 10023685 DOI: 10.1038/sj.onc.1202391] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Mdm2 protein is frequently overexpressed in human non-seminomatous germ cell tumours and transitional carcinoma of the bladder where it may contribute to tolerance of wtp53. Mdm2 forms an autoregulatory feedback loop with p53; the Mdm2 gene is responsive to transactivation by p53 and once synthesized the Mdm2 protein terminates the p53 response. We show here that the topoisomerase poison etoposide, like ultra violet irradiation, inhibits Mdm2 synthesis. Cytotoxic concentrations of etoposide (IC90 for > 3 h) result in inhibition of Mdm2 induction at both the RNA and protein level. Rapid apoptosis ensues. Global transcription is not inhibited: p21waf-1/cip1 and GADD45 expression increase in a dose dependent manner. Inhibition of Mdm2 synthesis depends on the continuous presence of etoposide, suggesting the DNA damage may prevent transcription. Downregulation of Mdm2 transcript occurs in cells expressing HPV16-E6 suggesting that inhibition of Mdm2 transcription is p53-independent. When cells are -treated with a pulse (1 h) of etoposide and reincubated in drug free medium, Mdm2 synthesis commences immediately after damage is repaired (3 h) and the p53 response is attenuated. Induction of apoptosis and loss of clonogenicity are 3-5-fold lower under pulse treatment conditions. This is the first observation of inhibition of Mdm2 transcription following treatment with topoisomerase (topo II) poisons, a feature that may be useful in tumour types where p53 is tolerated by overexpression of Mdm2.
Collapse
|
|
26 |
42 |
8
|
Lopez AR, Cook J, Deininger PL, Derynck R. Dominant negative mutants of transforming growth factor-beta 1 inhibit the secretion of different transforming growth factor-beta isoforms. Mol Cell Biol 1992; 12:1674-9. [PMID: 1549120 PMCID: PMC369610 DOI: 10.1128/mcb.12.4.1674-1679.1992] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Transforming growth factor-beta (TGF-beta) is a secreted polypeptide factor that is thought to play a major role in the regulation of proliferation of many cell types and various differentiation processes. Several related isoforms have been structurally characterized, three of which, TGF-beta 1, -beta 2, and -beta 3, have been detected in mammalian cells and tissues. Each TGF-beta form is a homodimer of a 112-amino-acid polypeptide which is encoded as a larger polypeptide precursor. We have introduced several mutations in the TGF-beta 1 precursor domain, resulting in an inhibition of TGF-beta 1 secretion. Coexpression of these mutants with wild-type TGF-beta 1, -beta 2, and -beta 3 results in a competitive and specific inhibition of the secretion of different TFG-beta forms, indicating that these mutated versions act as dominant negative mutants for TGF-beta secretion. Overexpression of dominant negative mutants can thus be used to abolish endogenous secretion of TGF-beta and structurally related family members, both in vitro and in vivo, and to probe in this way the physiological functions of the members of the TGF-beta superfamily.
Collapse
|
research-article |
33 |
10 |
9
|
Heacock ML, Lopez AR, Amolegbe SM, Carlin DJ, Henry HF, Trottier BA, Velasco ML, Suk WA. Enhancing Data Integration, Interoperability, and Reuse to Address Complex and Emerging Environmental Health Problems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7544-7552. [PMID: 35549252 PMCID: PMC9227711 DOI: 10.1021/acs.est.1c08383] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Indexed: 05/21/2023]
Abstract
Environmental health sciences (EHS) span many diverse disciplines. Within the EHS community, the National Institute of Environmental Health Sciences Superfund Research Program (SRP) funds multidisciplinary research aimed to address pressing and complex issues on how people are exposed to hazardous substances and their related health consequences with the goal of identifying strategies to reduce exposures and protect human health. While disentangling the interrelationships that contribute to environmental exposures and their effects on human health over the course of life remains difficult, advances in data science and data sharing offer a path forward to explore data across disciplines to reveal new insights. Multidisciplinary SRP-funded teams are well-positioned to examine how to best integrate EHS data across diverse research domains to address multifaceted environmental health problems. As such, SRP supported collaborative research projects designed to foster and enhance the interoperability and reuse of diverse and complex data streams. This perspective synthesizes those experiences as a landscape view of the challenges identified while working to increase the FAIR-ness (Findable, Accessible, Interoperable, and Reusable) of EHS data and opportunities to address them.
Collapse
|
Review |
3 |
8 |
10
|
Suk WA, Heacock ML, Trottier BA, Amolegbe SM, Avakian MD, Carlin DJ, Henry HF, Lopez AR, Skalla LA. Benefits of basic research from the Superfund Research Program. REVIEWS ON ENVIRONMENTAL HEALTH 2020; 35:85-109. [PMID: 32543458 DOI: 10.1515/reveh-2019-0104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/26/2020] [Indexed: 06/11/2023]
Abstract
The National Institutes of Health (NIH), National Institute of Environmental Health Sciences (NIEHS) Hazardous Substances Basic Research and Training Program [Superfund Research Program (SRP)] funds transdisciplinary research projects spanning the biomedical and environmental sciences to address issues related to potentially hazardous substances. We used a case study approach to identify how SRP-funded basic biomedical research has had an impact on society. We examined how transdisciplinary research projects from the SRP have advanced knowledge and led to additional clinical, public health, policy, and economic benefits. SRP basic biomedical research findings have contributed to the body of knowledge and influenced a broad range of scientific disciplines. It has informed the development of policies and interventions to reduce exposure to environmental contaminants to improve public health. Research investments by the SRP have had a significant impact on science, health, and society. Documenting the benefits of these investments provides insight into how basic research is translated to real-world applications.
Collapse
|
Review |
5 |
5 |
11
|
Heacock ML, Amolegbe SM, Skalla LA, Trottier BA, Carlin DJ, Henry HF, Lopez AR, Duncan CG, Lawler CP, Balshaw DM, Suk WA. Sharing SRP data to reduce environmentally associated disease and promote transdisciplinary research. REVIEWS ON ENVIRONMENTAL HEALTH 2020; 35:111-122. [PMID: 32126018 DOI: 10.1515/reveh-2019-0089] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/06/2020] [Indexed: 05/25/2023]
Abstract
The National Institute of Environmental Health Sciences (NIEHS) Superfund Basic Research and Training Program (SRP) funds a wide range of projects that span biomedical, environmental sciences, and engineering research and generate a wealth of data resulting from hypothesis-driven research projects. Combining or integrating these diverse data offers an opportunity to uncover new scientific connections that can be used to gain a more comprehensive understanding of the interplay between exposures and health. Integrating and reusing data generated from individual research projects within the program requires harmonization of data workflows, ensuring consistent and robust practices in data stewardship, and embracing data sharing from the onset of data collection and analysis. We describe opportunities to leverage data within the SRP and current SRP efforts to advance data sharing and reuse, including by developing an SRP dataset library and fostering data integration through Data Management and Analysis Cores. We also discuss opportunities to improve public health by identifying parallels in the data captured from health and engineering research, layering data streams for a more comprehensive picture of exposures and disease, and using existing SRP research infrastructure to facilitate and foster data sharing. Importantly, we point out that while the SRP is in a unique position to exploit these opportunities, they can be employed across environmental health research. SRP research teams, which comprise cross-disciplinary scientists focused on similar research questions, are well positioned to use data to leverage previous findings and accelerate the pace of research. Incorporating data streams from different disciplines addressing similar questions can provide a broader understanding and uncover the answers to complex and discrete research questions.
Collapse
|
Review |
5 |
5 |
12
|
Suk WA, Heacock M, Carlin DJ, Henry HF, Trottier BA, Lopez AR, Amolegbe SM. Greater than the sum of its parts: focusing SRP research through a systems approach lens. REVIEWS ON ENVIRONMENTAL HEALTH 2021; 36:451-457. [PMID: 32862150 DOI: 10.1515/reveh-2020-0073] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 07/28/2020] [Indexed: 05/25/2023]
Abstract
The National Institute of Environmental Health Sciences Superfund Research Program (SRP) funds diverse transdisciplinary research to understand how hazardous substances contribute to disease. SRP research focuses on how to prevent these exposures by promoting problem-based, solution-oriented research. SRP's mandate areas encompasses broad biomedical and environmental science and engineering research efforts and, when combined with research translation, community engagement, training, and data science, offers broad expertise and unique perspectives directed at a specific big picture question. The purpose of this commentary is to adapt a systems approach concept to SRP research to accommodate the complexity of a scientific problem. The SRP believes a systems approach offers a framework to understand how scientists can work together to integrate diverse fields of research to prevent or understand environmentally-influenced human disease by addressing specific questions that are part of a larger perspective. Specifically, within the context of the SRP, a systems approach can elucidate the complex interactions between factors that contribute to or protect against environmental insults. Leveraging a systems approach can continue to advance SRP science while building the foundation for researchers to address difficult emerging environmental health problems.
Collapse
|
|
4 |
4 |
13
|
Lopez AR, Hesterberg DR, Funk DH, Buchwalter DB. Bioaccumulation Dynamics of Arsenate at the Base of Aquatic Food Webs. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6556-64. [PMID: 27223406 DOI: 10.1021/acs.est.6b01453] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Periphyton is an important food source at the base of freshwater ecosystems that tends to bioconcentrate trace elements making them trophically available. The potential for arsenic-a trace element of particular concern due to its widespread occurrence, toxicity, and carcinogenicity-to bioconcentrate in periphyton and thus be available to benthic grazers is less well characterized. To better understand arsenate bioaccumulation dynamics in lotic food webs, we used a radiotracer approach to characterize accumulation in periphyton and subsequent trophic transfer to benthic grazers. Periphyton bioconcentrated As between 3,200-9,700-fold (dry weight) over 8 days without reaching steady state, suggesting that periphyton is a major sink for arsenate. However, As-enriched periphyton as a food source for the mayfly Neocloeon triangulifer resulted in negligible As accumulation in a full lifecycle exposure. Additional studies estimate dietary assimilation efficiency in several primary consumers ranging from 22% in the mayfly N. triangulifer to 75% in the mayfly Isonychia sp. X-ray fluorescence mapping revealed that As was predominantly associated with iron oxides in periphyton. We speculate that As adsorption to Fe in periphyton may play a role in reducing dietary bioavailability. Together, these results suggest that trophic movement of As in lotic food webs is relatively low, though species differences in bioaccumulation patterns are important.
Collapse
|
Research Support, N.I.H., Extramural |
9 |
4 |
14
|
Lopez AR, Barker J, Deisseroth AB. v-abl activates embryonic globin gene expression in mouse erythroleukemia cells. Proc Natl Acad Sci U S A 1986; 83:2042-6. [PMID: 3008148 PMCID: PMC323226 DOI: 10.1073/pnas.83.7.2042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The Philadelphia chromosome translocation, which is present in 90-95% of chronic myelogenous leukemia patients, involves translocation of the c-abl protooncogene to chromosome 22 and is accompanied by activation of embryonic globin gene expression in the K562 chronic myelogenous leukemia cell line. To test directly if the protein products of the translocated c-abl protooncogene can activate embryonic globin gene expression, we transfected the v-abl oncogene (which shares the property of autophosphorylation with the translocated c-abl protooncogene) into mouse erythroleukemia cells. v-abl-transfected mouse erythroleukemia cells, which contained multiple copies of the v-abl transgenome, exhibited activation of mouse embryonic globin gene expression. These results suggest that the translocated c-abl protooncogene of the Philadelphia chromosome translocation is central to the pathogenesis of chronic myelogenous leukemia and that it may result in the activation of embryonic globin genes in some chronic myelogenous leukemia cell lines.
Collapse
|
research-article |
39 |
3 |
15
|
Lopez AR, Funk DH, Buchwalter DB. Arsenic (V) bioconcentration kinetics in freshwater macroinvertebrates and periphyton is influenced by pH. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 224:82-88. [PMID: 28216132 DOI: 10.1016/j.envpol.2016.12.066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/19/2016] [Accepted: 12/21/2016] [Indexed: 05/26/2023]
Abstract
Arsenic is an important environmental pollutant whose speciation and mobility in freshwater food webs is complex. Few studies have characterized uptake and efflux rates of arsenic in aquatic benthic invertebrates. Further, we lack a fundamental understanding of how pH influences uptake kinetics in these organisms or how this key environmental variable could alter dietary exposure for primary consumers. Here we used a radiotracer approach to characterize arsenate accumulation dynamics in benthic invertebrates, the influence of pH on uptake in a subset of these organisms, and the influence of pH on uptake of arsenate by periphyton - an important food source at the base of aquatic food webs. Uptake rate constants (Ku) from aqueous exposure were modest, ranging from ∼0.001 L g-1d-1 in three species of mayfly to 0.06 L g-1d-1in Psephenus herricki. Efflux rate constants ranged from ∼0.03 d-1 in Corbicula fluminea to ∼0.3 d-1 in the mayfly Isonychia sp, and were generally high. Arsenate uptake decreased with increasing pH, which may be a function of increased adsorption at lower pHs. A similar but much stronger correlation was observed for periphyton where Ku decreased from ∼3.0 L g-1d-1 at 6.5 pH to ∼0.7 L g-1d-1 at 8.5 pH, suggesting that site specific pH could significantly alter arsenic exposure, particularly for primary consumers. Together, these findings shed light on the complexity of arsenic bioavailability and help explain observed differences reported in the literature.
Collapse
|
|
8 |
2 |
16
|
Lopez AR, Silva SC, Webb SM, Hesterberg D, Buchwalter DB. Periphyton and abiotic factors influencing arsenic speciation in aquatic environments. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2018; 37:903-913. [PMID: 29095518 DOI: 10.1002/etc.4025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/26/2017] [Accepted: 10/30/2017] [Indexed: 06/07/2023]
Abstract
Benthic periphytic biofilms are important food sources at the base of aquatic ecosystems. These biofilms also sit at the interface of oxic waters and hypoxic sediments, and can be influenced by or influence trace element speciation. In the present study, we compared arsenic (As) enrichment in periphyton exposed to arsenate (As[V]) or arsenite (As[III]) (20 μg/L, static renewal, 7 d), and we found similar accumulation patterns of total As (101 ± 27 and 88 ± 22 mg kg-1 dry wt, respectively). Periphyton As was 6281- and 6684-fold higher than their aqueous exposures and occurred primarily as As(V). When these biofilms were fed to larval mayflies, similar total As tissue concentrations (13.9 and 14.6 mg kg-1 dry wt, respectively) were observed, revealing significant biodilution (∼ 10% of their dietary concentrations). Finally, we investigated the influence of aeration and periphyton presence on As speciation in solutions and solid phases treated with As(III). Predominantly As(III) solutions were slowly oxidized over a 7-d time period, in the absence of periphyton, and aeration did not strongly affect oxidation rates. However, in the presence of periphyton, solution and solid-phase analyses (by microscale x-ray absorption spectroscopy) showed rapid As(III) oxidation to As(V) and an increasing proportion of organo-As forming over time. Thus periphyton plays several roles in As environmental behavior: 1) decreasing total dissolved As concentrations via abiotic and biotic accumulation, 2) rapidly oxidizing As(III) to As(V), 3) effluxing organo-As forms into solution, and 4) limiting trophic transfer to aquatic grazers. Environ Toxicol Chem 2018;37:903-913. © 2017 SETAC.
Collapse
|
|
7 |
2 |
17
|
Chang HL, Gillett N, Figari I, Lopez AR, Palladino MA, Derynck R. Increased transforming growth factor beta expression inhibits cell proliferation in vitro, yet increases tumorigenicity and tumor growth of Meth A sarcoma cells. Cancer Res 1993; 53:4391-8. [PMID: 8364935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Several observations correlate increased expression of transforming growth factor (TGF) beta 1 with tumorigenesis, suggesting that expression of this multifunctional growth factor may provide an advantage in tumor formation. However, many tumor cells are inhibited in their proliferation by TGF-beta in vitro, thus suggesting that TGF-beta synthesis could exert an antiproliferative effect on tumor formation. To evaluate the physiological relevance of increased TGF-beta 1 synthesis in such tumor cells which are strongly inhibited in their proliferation by TGF-beta, we chose Meth A sarcoma cells as a model system. We established cell clones overexpressing TGF-beta 1 and determined its effect on tumor formation in mice that are not immunocompromised. Increased expression of biologically active TGF-beta 1 resulted in a profound growth inhibition in the transfected clones and increased adhesiveness in vitro. However, these cells were much more tumorigenic than Meth A cells that did not overexpress TGF-beta 1, as assessed by both tumor incidence and tumor growth. In addition, parental Meth A cells were inhibited in their tumor formation by neutralizing TGF-beta antibodies and stimulated by exogenous TGF-beta. Our results thus provide evidence that increased TGF-beta synthesis provides a major advantage for tumorigenesis, even if the cells are growth inhibited by their endogenous TGF-beta synthesis in culture. These results suggest that, in vivo, direct effects of TGF-beta on the tumor environment, such as increased extracellular matrix formation and cell-matrix interactions, and local suppression of the immune surveillance may provide a growth advantage which overrules any direct antiproliferative effects of TGF-beta, as suggested by the effects in culture.
Collapse
|
|
32 |
|
18
|
Lopez AR, Lopez TA. [Analysis of dermatoglyphics in essential epilepsy]. ARCHIVOS DE NEUROBIOLOGIA 1977; 40:347-62. [PMID: 597002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
English Abstract |
48 |
|
19
|
Lawrence HJ, Sauvageau G, Ahmadi N, Lopez AR, LeBeau MM, Link M, Humphries K, Largman C. Stage- and lineage-specific expression of the HOXA10 homeobox gene in normal and leukemic hematopoietic cells. Exp Hematol 1995; 23:1160-6. [PMID: 7556525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
There is growing evidence that the HOX homeobox-containing transcription factors are differentially expressed during hematopoiesis. We have previously demonstrated that the HOXA10 gene is expressed in unfractionated normal marrow and in immortalized leukemic cell lines with myelomonocytic features, but not in cell lines with lymphoid or erythroid features. To gain insights into the patterns of activation of this gene during hematopoietic differentiation, we have examined HOXA10 expression in CD34+ and CD34- subfractions of normal marrow and normal peripheral blood, as well as samples from patients with a variety of acute and chronic leukemias. HOXA10 is strongly expressed in CD34+ normal marrow cells, markedly downregulated in CD34- marrow cells, and inactive in mature neutrophils, monocytes, and lymphocytes. HOXA10 is expressed in all types of acute myelogenous leukemia (AML) with the notable exception of acute promyelocytic leukemia (AML-M3). HOXA10 message is observed in chronic myelogenous leukemia (CML) but appears to be reduced in accelerated phase and blast crisis, particularly lymphoid blast crisis. With rare exception, HOXA10 expression is not observed in samples of acute or chronic lymphoid leukemias. Normal marrow and patient samples appear to contain a single transcript which encodes a full-length homeobox-containing protein, while immortalized cell lines contain an additional alternatively spliced transcript. These studies indicate that HOXA10 expression is restricted to early stages of myeloid differentiation.
Collapse
MESH Headings
- Base Sequence
- Blotting, Southern
- Bone Marrow/metabolism
- Bone Marrow/pathology
- Bone Marrow Cells
- Cell Line
- Cells, Cultured
- DNA/analysis
- DNA Primers
- DNA, Complementary
- DNA, Neoplasm/analysis
- Gene Expression
- Genes, Homeobox
- Hematopoietic Stem Cells/cytology
- Hematopoietic Stem Cells/metabolism
- Hematopoietic Stem Cells/pathology
- Homeodomain Proteins/biosynthesis
- Humans
- Leukemia/metabolism
- Leukemia/pathology
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Leukemia, Promyelocytic, Acute/metabolism
- Molecular Sequence Data
- Myelodysplastic Syndromes/metabolism
- Polymerase Chain Reaction
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism
- Reference Values
- Transcription, Genetic
Collapse
|
Comparative Study |
30 |
|
20
|
Smarr MM, Avakian M, Lopez AR, Onyango B, Amolegbe S, Boyles A, Fenton SE, Harmon QE, Jirles B, Lasko D, Moody R, Schelp J, Sutherland V, Thomas L, Williams CJ, Dixon D. Broadening the Environmental Lens to Include Social and Structural Determinants of Women's Health Disparities. ENVIRONMENTAL HEALTH PERSPECTIVES 2024; 132:15002. [PMID: 38227347 PMCID: PMC10790815 DOI: 10.1289/ehp12996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 12/06/2023] [Accepted: 12/14/2023] [Indexed: 01/17/2024]
Abstract
BACKGROUND Due to the physical, metabolic, and hormonal changes before, during, and after pregnancy, women-defined here as people assigned female at birth-are particularly susceptible to environmental insults. Racism, a driving force of social determinants of health, exacerbates this susceptibility by affecting exposure to both chemical and nonchemical stressors to create women's health disparities. OBJECTIVES To better understand and address social and structural determinants of women's health disparities, the National Institute of Environmental Health Sciences (NIEHS) hosted a workshop focused on the environmental impacts on women's health disparities and reproductive health in April 2022. This commentary summarizes foundational research and unique insights shared by workshop participants, who emphasized the need to broaden the definition of the environment to include upstream social and structural determinants of health. We also summarize current challenges and recommendations, as discussed by workshop participants, to address women's environmental and reproductive health disparities. DISCUSSION The challenges related to women's health equity, as identified by workshop attendees, included developing research approaches to better capture the social and structural environment in both human and animal studies, integrating environmental health principles into clinical care, and implementing more inclusive publishing and funding approaches. Workshop participants discussed recommendations in each of these areas that encourage interdisciplinary collaboration among researchers, clinicians, funders, publishers, and community members. https://doi.org/10.1289/EHP12996.
Collapse
|
case-report |
1 |
|
21
|
Deisseroth AB, Purohit S, Lopez AR. Chronic myelogenous leukemia--recent advances in treatment and pathogenesis. West J Med 1986; 144:338-43. [PMID: 3457494 PMCID: PMC1306611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
research-article |
39 |
|
22
|
Lopez AR, Nguyen AV, Williams K, Kwan L, Hwang LY, Rible RD. P069Adolescent patients’ comfort discussing contraception: Comparing physicians’ perceptions and adolescents’ self-reported preferences. Contraception 2022. [DOI: 10.1016/j.contraception.2022.09.093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
|
3 |
|
23
|
Amolegbe SM, Lopez AR, Velasco ML, Carlin DJ, Heacock ML, Henry HF, Trottier BA, Suk WA. Adapting to Climate Change: Leveraging Systems-Focused Multidisciplinary Research to Promote Resilience. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:14674. [PMID: 36429393 PMCID: PMC9690097 DOI: 10.3390/ijerph192214674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/02/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Approximately 2000 official and potential Superfund sites are located within 25 miles of the East or Gulf coasts, many of which will be at risk of flooding as sea levels rise. More than 60 million people across the United States live within 3 miles of a Superfund site. Disentangling multifaceted environmental health problems compounded by climate change requires a multidisciplinary systems approach to inform better strategies to prevent or reduce exposures and protect human health. The purpose of this minireview is to present the National Institute of Environmental Health Sciences Superfund Research Program (SRP) as a useful model of how this systems approach can help overcome the challenges of climate change while providing flexibility to pivot to additional needs as they arise. It also highlights broad-ranging SRP-funded research and tools that can be used to promote health and resilience to climate change in diverse contexts.
Collapse
|
Review |
3 |
|